This invention relates to the field of rail road cars for carrying wheeled vehicles.
Railroad flat cars are used to transport highway trailers from one place to another in what is referred to as intermodal Trailer-on-Flat-Car (TOFC) service. TOFC service competes with intermodal container service known as Container-on-Flat-Car (COFC), and with truck trailers driven on the highway. TOFC service has been in relative decline for some years due to a number of disadvantages.
First, for distances of less than about 500 miles (800 km), TOFC service is thought to be slower and less flexible than highway operation. Second, in terms of lading per rail car, TOFC tends to be less efficient than Container-on-Flat-Car (COFC) service, and tends also to be less efficient than double-stack COFC service in which containers are carried on top of each other. Third, TOFC (and COFC) terminals tend to require significant capital outlays. Fourth, TOFC loading tends to take a relatively long time to permit rail road cars to be shunted to the right tracks, for trailers to be unloaded from incoming cars, for other trailers to be loaded, and for the rail road cars to be shunted again to make up a new train consist. Fifth, shock and other dynamic loads imparted during shunting and train operation may tend to damage the lading. It would be advantageous to improve rail road car equipment to reduce or eliminate some of these disadvantages.
As highways have become more crowded, demand for a fast TOFC service has increased. Recently, there has been an effort to reduce the loading and unloading time in TOFC service, and an effort to increase the length of TOFC trains. There are two methods for loading highway trailers on flat cars. First, they can be side-loaded with an overhead crane or side-lifting fork-lift crane. Loading with overhead cranes, or with specialized fork-lift equipment tends to occur at large yards, and tends to be capital intensive.
The second method of loading highway trailers, or other wheeled vehicles, onto rail road cars having decks for carrying vehicles, is by end-loading. End-loading, or circus loading as it is called, has two main variations. First, a string of cars can be backed up to a permanently fixed loading dock, typically a concrete structure having a deck level with the deck of the rail cars. Alternatively, a movable ramp can be placed at one end of a string of rail car units. In either case, the vehicles are driven onto the rail road cars from one end. Each vehicle can be loaded in sequence by driving (in the case of highway trailers, by driving the trailers backward) along the decks of the rail road car units. The gaps between successive rail car units are spanned by bridge plates that permit vehicles to be driven from one rail car unit to the next. Although circus loading is common for a string of cars, end-loading can be used for individual rail car units, or multiple rail car units as may be convenient.
One way to reduce shunting time, and to run a more cost effective service, is to operate a dedicated unit train of TOFC cars whose cars are only rarely uncoupled. However, as the number of units in the train increases, circus loading becomes less attractive, since a greater proportion of loading time is spent running a towing rig back and forth along an empty string of cars. It is therefore advantageous to break the unit train in several places when loading and unloading. Although multiple fixed platforms have been used, each fixed platform requires a corresponding dedicated dead-end siding to which a separate portion of train can be shunted. It is not advantageous to require a large number of dedicated parallel sidings with a relatively large fixed investment in concrete platforms.
To avoid shunting to different tracks, as required if a plurality of fixed platforms is used, it is advantageous to break a unit train of TOFC rail road cars on a single siding, so that the train can be re-assembled without switching from one track to another. For example, using a 5000 or 6000 ft siding, a train having 60 rail car units in sections of 15 units made up of three coupled five-pack articulated cars, can be split at two places, namely fifteen units from each end, permitting the sequential loading of fifteen units per section to either side of each split. Once loaded, the gaps between the splits can be closed, without shunting cars from one siding to another. Use of a single siding is made possible by moving the ramps to the split location, rather than switching strings of cars to fixed platforms.
In using movable ramps for loading, the highway trailers are typically backed onto the railcars using a special rail yard truck, called a hostler truck. Railcars can be equipped with a collapsible highway trailer kingpin stand. When the highway trailer is in the right position, the hostler truck hooks onto the collapsible stand (or hitch) and pulls it forward, thereby lifting it to a deployed (i.e., raised) and locked position. The hostler truck is then used to push the trailer back to engage the kingpin of the hitch. The landing gear of the highway trailer is lowered, and, in addition, it is cranked downward firmly against the rail road car deck as a safety measure in the event of a hitch failure or the king pin of the trailer is sheared off. Once one trailer has been loaded, the towing rig, namely the hostler truck, drives back to the end of the string, another trailer is backed into place, and the process is repeated until all of the trailers have been loaded in the successive positions on the string of railcars. Unloading involves the same process, in reverse. In some circumstances, circus loaded flat cars can be loaded with trucks, tractors, farm machinery, construction equipment or automobiles, in a similar manner, except that it is not always necessary to use a towing rig.
From time to time, the train consist may be broken up, with various highway-trailer-carrying rail road cars being disconnected, and others being joined. Bridge plates have been the source of some difficulties at the rail car ends where adjacent railroad cars are connected, given the nomenclature xe2x80x9cthe coupler endsxe2x80x9d. Traditionally, a pair of cars to be joined at a coupler would each be equipped with one bridge plate permanently mounted on a hinged connection on one side of the car, typically the left hand side. In this arrangement the axis of the hinge is horizontal and transverse to the longitudinal centerline of the rail car.
Conventionally, for loading and unloading operations, the bridge plate of each car at the respective coupled end is lowered, like a draw bridge, into a generally horizontal arrangement to mate with the adjoining car, each plate providing one side of the path so that the co-operative effect of the two plates is to provide a pair of tracks along which a vehicle can roll. When loading is complete, the bridge plates are pivoted about their hinges to a generally vertical, or raised, position, and locked in place so that they cannot fall back down accidentally.
Conventionally, bridge plates at the coupler ends are returned to the raised, or vertical, position before the train can move, to avoid the tendency to become jammed or damaged during travel. That is, as the train travels through a curve, the bridge plates would tend to break off if left in the spanning position between the coupler ends of two rail road cars. Since bridge plates carry multi-ton loads, they tend to have significant structure and weight. Consequently, the requirement to raise and lower the bridge plates into position is a time consuming manual task contributing to the relatively long time required for loading and unloading. Raising and lowering bridge plates may tend to expose rail-yard personnel to both accidents and repetitive strain injuries caused by lifting.
It would be advantageous to have (a) a bridge plate that can be moved to a storage, or stowed, position, with less lifting; (b) a bridge plate system that does not require the bridge plate to be moved by hand as often, such as by permitting the bridge plate to remain in place during train operation, rather than having to be lowered every time the train is loaded and unloaded, and raised again before the train can move.
Further, a rail road car may sometimes be an internal car, with its bridge plates extended to neighbouring cars, and at other times the rail road car may be an xe2x80x9cendxe2x80x9d car at which the unit train is either (a) split for loading and unloading; (b) coupled to the locomotive; or (c) coupled to another type of rail road car. In each case, the bridge plate at the split does not need to be in an extended xe2x80x9cdrive-overxe2x80x9d position, and should be in a stowed position. Therefore it is advantageous to have a rail car with bridge plates that can remain in position during operation as an internal car in a unit train, and that can also be stowed as necessary when the car is placed in an end or split position.
However, a bridge plate that is to be left in place to span a gap between adjacent releasably coupled vehicle carrying rail road cars while the train is moving must be able to accommodate relative pitch, yaw, roll and slack action motions between the coupler ends of two adjacent cars during travel. For example, when a train travels through a curve, the gap spanned by the bridge plate on the inside of the curve will shorten, and the gap spanned by the bridge plate on the outside of the curve will lengthen. When passing over switches, the coupler ends of adjacent railroad cars may be subject to both angular and transverse displacement relative to each other. All of these displacements are complicated by the need to tolerate slack action. Slack action includes not only the actual slack in the couplers themselves, but also the run-in and run-out of the draft gear, (or sliding sills, or end of car cushioning devices) of successive rail cars in the train. This combination of displacements does not occur at the articulated connectors between units of an articulated rail road car (which are joined at a common, virtually slackless pin), but does occur at the coupler ends. If the vehicle carrying rail road cars have long travel draft gear, such as sliding sills or long travel end of car cushioning (EOCC) units, the potential range of motion that would have to be tolerated by stay-in-place bridge plates at the xe2x80x9cdrive-overxe2x80x9d coupler ends of railroad cars would be quite large relative to the nominal gap to be spanned with the cars at an undeflected equilibrium on straight, flat track.
One approach is to reduce the amount and type of train motion to which stay-in-place bridge plates may be subjected. It is advantageous to reduce the amount of slack in the releasable coupling, as by using a reduced slack or slackless coupler, and to reduce the travel in the draft gear, as by using reduced travel draft gear. In addition, reduction in overall slack action in the train has a direct benefit in improving ride quality, and hence reducing damage to lading.
One way to reduce slack action is to use fewer couplings. To that end, since articulated connectors are slackless, and since the consist of a unit train changes only infrequently, the use of articulated rail road cars significantly reduces the slack action in the train. Some releasable couplings are still necessary, since the consist does sometimes change, and it is necessary to change out a car for repair or maintenance when required.
Reduction in the travel of draft gear or end-of-car cushioning units (EOCC) runs directly counter to the development of draft gear since the 1920""s or 1930""s. There has been a long history of development of longer travel draft gear to provide lading protection for relatively high value lading requiring gentler handling, in particular automobiles and auto parts, but also farm machinery, or tractors, or highway trailers. There are, or were, a number of factors that led to this tendency. First, if subject to general classification in a switching yard, the vehicle carrying rail road cars could be coupled to other types of car, rather than merely other vehicle carrying cars. As such, they would be subject to slack run-in (i.e, buff) loads imposed by grain cars, gondola cars, box cars, centerbeam cars, and so on. That is, they were exposed to buff loads from cars having the full range of slack of Type-E couplers, and the full range of travel of conventional draft gear. Second, if subject to flat switching, the often less than gentle habits of rail yard personnel might lead to rather high impact loads during coupling.
In such a hostile operating environment, long travel draft gear or long travel EOCC units are the customary means for protecting the more fragile types of lading. Historically, common types of draft gear, such as that complying with, for example, AAR specification M-901-G, have been rated to withstand an impact at 5 m.p.h. (8 km/h) at a coupler force of 500,000 lbs. (roughly 2.2xc3x97106 N). Typically, these draft gear have a travel of 2xc2xe to 3xc2xc inches in buff before reaching the 500,000 lbs. load, and before xe2x80x9cgoing solidxe2x80x9d. The term xe2x80x9cgoing solidxe2x80x9d refers to the point at which the draft gear exhibits a steep increase in resistance to further displacement. While deflection of about 3 inches at 500,000 lbs. buff load may be acceptable for coal or grain, it implies undesirably high levels of acceleration or deceleration for more fragile lading, such as automobiles or auto parts. If the impact is sufficiently large to make the draft gear xe2x80x9cgo solidxe2x80x9d, then the force transmitted, and the corresponding acceleration imposed on the lading, increases sharply.
Draft gear development has tended to be directed toward providing longer travel on impact to reduce the peak acceleration. In the development of sliding sills, and latterly, hydraulic end of car cushioning units, the same impact is accommodated over 10, 15, or 18 inches of travel. Given this historical development, it is counter-intuitive to employ short-travel, or ultra short travel, draft gear for carrying wheeled vehicles. However, aside from facilitating the use of stay-in-place coupler end bridge plates, the use of short travel, or ultra-short travel, buff gear has the advantage of eliminating the need for relatively expensive, and relatively complicated EOCC units, and the fittings required to accommodate them. This may tend to permit savings both at the time of manufacture, and savings in maintenance during service.
Short travel draft gear is presently available. As noted above, most M-901-G draft gear xe2x80x9cgo solidxe2x80x9d at an official rating travel of 2xc2xexe2x80x3 to 3xc2xcxe2x80x3 of compression under a buff load of several hundreds of thousands of pounds. Mini-BuffGear, as produced by Miner Enterprises Inc., of 1200 State Street, Geneva, Ill., appears to have a displacement of less than 0.7 inches at a buff load of over 700,000 lbs., and a dynamic load capacity of 1.25 million pounds at 1 inch travel.
Furthermore, in seeking a low slack, or slackless train, it is desirable to adopt low-slack, or slackless couplings. Although reduced slack AAR Type F couplers have been known since the 1950""s, and slackless xe2x80x9ctightlockxe2x80x9d AAR Type H couplers became an adopted standard type on passenger equipment in 1947, AAR Type E couplers are still predominant. AAR Type H couplers are expensive, and are used for passenger cars, as are the alternate standard Type CS controlled slack couplers. According to the 1997 Cyclopedia, supra, at p. 647 xe2x80x9cAlthough it was anticipated at one time that the F type coupler might replace the E as the standard freight car coupler, the additional cost of the coupler and its components, and of the car structure required to accommodate it, have led to its being used primarily for special applicationsxe2x80x9d. One xe2x80x9cspecial applicationxe2x80x9d for F type couplers is in tank cars.
The difference between the nominal xe2x85x9cxe2x80x3 slack of a Type F coupler and the nominal {fraction (25/32)}xe2x80x3 slack of a Type E coupler may seem small in the context of EOCC equipped cars having 10, 15 or 18 inches of travel. By contrast, that difference, {fraction (13/32)}xe2x80x3, seems proportionately larger when viewed in the context of the approximately {fraction (11/16)}xe2x80x3 buff compression (at 700,000 lbs.) of Mini-BuffGear. It should be noted that there are many different styles of Type E and Type F couplers, whether short or long shank, whether having upper or lower shelves. There is a Type E/F having a Type E coupler head and a Type F shank. There is a Type E50ARE knuckle which reduces slack from {fraction (25/32)}xe2x80x3 to {fraction (20/32)}xe2x80x3. Type F herein is intended to include all variants of the Type F series, and Type E herein is intended to include all variants of the Type E series having {fraction (20/32)}xe2x80x3 of slack or more.
Stay-in-place bridge plates are intended to accommodate the range of travel defined by the combination of coupler and draft gear, given anticipated service loads. While it may be possible to operate telescoping bridge plates, they are relatively less advantageous than monolithic bridge plates. First, a telescoping device may require a more challenging installation procedure if two sliding parts have to be inserted in each other. Second, the telescoping device must be able to telescope, and yet must also be able to support the vertical load carried on the slide. A slide with significant tolerance may not necessarily support bending moments well, may tend to wear under repeated loading, and may cease to slide very well if damaged or bent due to the vertical loads. A monolithic beam has no moving parts requiring careful manufacturing tolerance, and has no moving parts that may deform and jam in service. Slides may accumulate sand and dirt, and may cease to function if water is able to freeze in the slide.
Loading and unloading of highway trailers, or other vehicles in the manner described above, can also be a relatively tedious and time consuming chore, particularly as the number of railroad cars in the string increases. Persons engaged in such activity may, after some time, perhaps late at night, tend to become less fastidious in their conduct. They may tend to become overconfident in their abilities, and may tend to try to back the highway trailers on to the rail cars rather more quickly than may be prudent. It has been suggested that speeds in the order of 20 km/h have been attempted. In the past, it has been difficult to form bridge plates that lie roughly flush with the deck. Due to their strength requirement, they tend to be about 2 inches thick or more. As a result there is often a significant bump at the bridge plate. Aggressive loading and unloading of the trailers may cause an undesirable impact at the bump, and loss of control of the load. In that regard, it would be advantageous to reduce the height or severity of the bump. It is also advantageous to employ side sills that have a portion, such as the side sill top chord, that extends above the height of the deck and acts as a curb bounding the trackway, or roadway, defined between the side sills. It is also helpful to have flared sill, or curb, ends that may tend to aid in urging highway trailers toward the center of the trackway along the rail cars.
In an aspect of the invention there is a process for moving a bridge plate of a vehicle carrying rail road car from a length-wise position to a cross-wise position relative to the rail road car. The vehicle carrying rail road car has a rail road car body, mounted on rail road car trucks for rolling operation in a longitudinal direction and a vehicle deck mounted to the body. The vehicle deck has a first end. A bridge plate is mounted to the first end. The bridge plate is movable from a length-wise position relative to the rail car body to a cross-wise position relative to the rail car body. The process including, establishing the bridge plate in the lengthwise position relative to the rail road car body, and moving the bridge plate from the length-wise position to the cross-wise position.
In an additional feature of that aspect of the invention, the step of moving is followed by the step of securing the bridge plate in the cross-wise position with a retainer. In another additional feature, the step of moving includes swinging the bridge plate about a pivot mounting on the rail car body. In a still further feature, the step of swinging includes pivoting the bridge plate in a horizontal plane.
In an additional feature of that aspect of the invention the step of moving the bridge plate is preceded by the step of disengaging a distal tip of the bridge plate from an adjacent rail road car. In another additional feature, the step of disengaging the distal tip of the bridge plate from an adjacent car includes the step of uncoupling the adjacent car from the railroad car. In still another additional feature, the rail road car has a transition plate mounted between the deck and the bridge plate, wherein the step of moving the bridge plate is preceded by the step of disengaging the transition plate from the bridge plate. The step of moving the bridge plate is followed by the step of re-engaging the transition plate with the bridge plate. In yet another additional feature, the step of disengaging the transition plate includes raising at least a portion of the transition plate to a position clear of the bridge plate. In still yet another additional feature, the step of re-engaging includes lowering at least a portion of the transition plate to an overlapping position relative to the bridge plate.
In a further additional feature, the step of disengaging the transition plate from the bridge plate includes the step of operating a crank to lift at least a portion of the transition plate. In yet another additional feature, the step of operating the crank includes the step of turning the crank to cause a cam member to bear against the transition plate. In still another additional feature, the crank has an input torque fitting extending laterally from the rail car body, and the step of operating the crank includes engaging a lever arm to the torque fitting and applying a force to turn the crank. In still yet another additional feature, the step of securing includes engaging a retainer fitting to the bridge plate and to the rail car body to maintain the bridge plate in the stowed position.
In another aspect of the invention, there is a process for coupling two rail road cars for carrying vehicles. Each of the rail road cars has a rail road car body supported for rolling motion in a longitudinal direction. The rail car body has a first end and a second end distant therefrom. The first end has a releasable coupler mounted thereto. There is a deck for carrying wheeled vehicles. The deck has a coupler end. A bridge plate is mounted to the first end of the rail car body. The process includes the steps of positioning the respective bridge plates of the rail road cars in a length-wise orientation relative thereto and advancing the rail road cars toward each other to cause their respective couplers to mate. The step of advancing including the step of engaging an extended portion of each of the bridge plates with a receiving member of the other of said rail cars.
In a further additional feature, in the lengthwise orientation the bridge plates have a proximal portion mounted to respective ones of the rail car bodies, and a distal tip located longitudinally outboard of the respective car bodies. The step of positioning each of the bridge plates includes securing the distal tip in a raised attitude relative to the proximal portion. In another additional feature, the step of engaging includes lowering the distal tip onto the receiving member. In a further feature, each receiving member includes a shelf, and the step of engaging includes locating a tip of each bridge plates on each the shelf respectively. In a still further additional feature, the step of engaging includes a step of securing each bridge plate to the other of the rail road cars. In a yet further additional feature, the step of engaging includes retaining a distal tip of each of the bridge plates in place by linking a slot thereof to a socket of the other rail road car with a hinge pin.
In a further additional aspect of the invention, each of the rail road cars has a transition plate mounted adjacent to the receiving member. The step of advancing is preceded by the step of moving the transition plates to a first position to facilitate engagement of the bridge plate with the receiving member. The step of engaging is followed by the step of placing the transition plate between the received distal tip of the bridge plate of one of the rail road cars and the vehicle carrying deck of the other of the rail road cars. In an additional feature of that additional feature, the step of placing includes lowering a portion of the transition plate to an overlapping position relative to the distal tip of the bridge plate.
In another additional feature, the step of moving the transition plate to the first position includes the step of raising at least a portion of the transition plate to a raised position. In a further additional feature, the step of raising the transition plate includes the step of employing a prop to maintain the transition plate in the raised position. In a still further feature, the step of engaging includes advancing the bridge plate to disengage the prop, the act of disengaging the prop causing the transition plate to move to an overlapping position relative to the distal tip of the bridge plate. In a further feature, the step of raising includes operating a cam crank to lift at least the portion of the transition plate.
In a yet further additional feature, the step of positioning includes moving the bridge plates from a cross-wise storage position relative to the respective rail car bodies. In a further feature, the step of moving the bridge plates from the stored position includes pivoting the bridge plates in a horizontal plane from the cross-wise storage position to the length-wise orientation. In another further feature, the step of positioning is preceded by the step of releasing a retaining member to permit the bridge plate to move from the stored position to the length-wise orientation.